The principal objective of this proposal is to determine the nature, quantitative relationships and the mechanisms by which hormones interact in myometrium and endometrium. Employing rat uterus preparations, the quantitative relations between isoproterenol, prostaglandins, oxytocin, estrogens and progesterone in controlling adenyl cyclase activity (measuring both adenyl cyclase and cAMP) protein kinase activation (measuring both cAMP binding and catalytic activity in the presence or absence of an excess of cAMP) and myometrial contractility will be studied. The relation of the above to Ca2 plus transfer between cell compartments and bathing medium will be investigated in an attemp to discern why skeletal muscle contractility is enhanced and smooth muscle is inhibited by elevation of cAMP. A relationship between adenyl cyclase activity and early uterine responses to estrogen, including nuclear hormone uptake and induced protein synthesis will be sought. Myometrial protein kinase will be purified, its components prepared in the manner recently described and the kinetics of the cAMP receptor action determined.